单相接地故障下第2个反向行波识别的新方法

在三相线路上发生单相接地故障时，线模行波极性受保护线路两侧的母线结构和测量点行波大小的影响，基于单端线模行波极性正确识别第2个反向行波是故障点反射波还是对端母线反射波非常困难。针对此问题，提出了不受线路两侧母线结构影响的第2个反向行波识别新原理，若第2个到达测量点的反向行波中零模与线模行波极性相同，则为故障点反射波；若零模与线模行波极性相反，则为从故障点透射过来的对端母线反射波，大量EMTP仿真证明了此原理清晰、可靠，方法有效、正确。

New Principle to Identify the Second Reverse Traveling Wave Generated by Single-phase-to-ground Fault

Identification of traveling wave reflected by fault point or by bus at remote end is the core of traveling wave based distance protection and fault location based on single-end traveling wave. However, when single-phase-to-ground fault occurs in the three-phase transmission lines, the polarity of traveling waves is affected by the configuration of buses at both ends of protected lines and traveling waves obtained at measurement. In this case, it is difficult to identify if the second reverse traveling wave is reflected from fault point or the bus at the remote end. This paper presents a new principle based on the polarity relation of zero module and line module of the second reverse direction traveling waves, which is independent of the configuration of buses. If the relation of zero module and line module is the same, the traveling wave is reflected from the fault point; otherwise, from the bus at the remote end. EMTP simulation shows that the principle is correct and reliable.